Refrigerating apparatus

ABSTRACT

A refrigerating apparatus for conditioning an enclosed space such as a truck trailer body and including means for selectively drawing a partial vacuum within the space such that perishable food products may be rapidly cooled by vaporizing the moisture thereon, and means for selectively pressurizing the space to prevent dehydration of the food products during relatively long term storage.

United States Patent [191 [111 3,786,652 Bolynn 1 Jan. 22, 1974 REFRIGERATING APPARATUS 2,475,077 5/1949 Clancy 62/89 2,478,719 8/1949 Skinner 62/78 [76] went axat g-ggg'g gf- 8112 2,894,845 7/1959 Stoddard 62/89 [22] Filed: July 18, 1972 Primary Examiner-William J. Wye 1 pp No 272 786 Attorney, Agent, or FirmDaniel E. McConnell v [57] ABSTRACT [52] US. Cl 62/243, 62/78, 62/89, f

62/241 62/242, 62/268, 62/100 A refrigerating apparatus or conditioning an enclosed [51] Int. Cl B60h 3/04 Space sue]? as a truck, miller and mcludmg {mans [58] Field of Search" 62/268 78 89, 241, 242, 243 for selectively dravymg a partial vacuum withm the space such that perishable food products may be rap- [56] References Cited idly cofled 51y tyaplorizing the moisture thetreon, anctl means or se ec ive y pressurizmg e space 0 preven l 947 223 Z I'TT PATENTS 62/89 dehydration of the food products during relatively p u s 2,109,002 2/1938 Warren 62/267 long term Storage 2,345,204 3/1944 Lodwig 98/29 5 Claims, 2 Drawing Figures 225 I37 TEAQTJR, E'NG-lNE A12, ComPaessoR.

Moron Pump PATENTEQ JAN 2 2 m4 TRACTOR, ENG-\NE Am, COMPRESSOR COMP. MOTOR 4- CONDENSER REFRIGERATING APPARATUS The present invention relates to refrigerating apparatus having provision for selectively controlling the pressure conditions within the refrigerated storage space.

To facilitate the shipment of perishable food and other products, such as fresh produce, freshly slaughtered carcasses, fresh flowers and the like, special refri'geration trucks have been developed which are designed to maintain the enclosed trailer storage space at an appropriate temperature. Typically, such refrigerated trucks include a vapor compression cycle refrigeration producer having a compressor, a condenser, an evaporator, and a blower or fan for circulating the air within the conditioned space in heat exchange relation with the evaporator.

In the shipment of certain goods, such as hot produce being loaded into the trailer directly from the field where grown, it has been found that the conventional refrigeration producer is often inadequate to promptly cool the goods to the desired temperature. Thus, signif' icant spoilage of the goods can occurbefore the goods are brought to the desired temperature.

A further problem in the shipment of perishable goods arises when the goods are shipped for long distances. in such cases, there is often a significant loss in weight of the goodsresulting from their slow dehydration, which of course reduces the commercial value of the goods. While some success in alleviating this problem has beenachieved by increasing the humidity of the air within the'trailer, the equipmentfor accomplishing such humidity controlis relatively expensive and not altogether adequate to prevent dehydration in some cases. I a It is accordingly an object of the present invention to provide a refrigerating apparatus which is adapted to quickly cool a hot" load of fresh produce or the like, while employing a refrigeration unit of conventional size or capacity.

It is another objectof the present invention to provide a refrigerating apparatus which includes relatively simple and inexpensive means for reducing the dehydration of food products which would normally occur when stored for a relatively long period of time.

In accordance with the present invention, it has been found thatthe above objects and advantages may be achieved by a refrigerating apparatus which includes means for selectively pressurizing the trailer body. In addition, means are provided for drawing a partial vacuum within the trailer body. In use, the vacuum means is employed to rapidly cool the goods by evaporating the moisture thereon, such moisture normally consisting only of the moisture on the surface of the goods.

Once the desired temperature is reached, the pressur- FIG. I is an elevation view, partly broken away, of an automotive trucking vehicle incorporating a refrigerating apparatus in accordance with the present invention; a

and

FIG. 2 is a schematic representation of the trailer body shown in FIG. 1 and illustrating the refrigeration apparatus of the-present invention.

Referring more specifically to the drawings, an automotive trucking vehicle is indicated generally at 10 and includes the conventional tractor 12 having a gasoline powered or diesel engine 13, and a trailer body 14 defining an enclosed storage space 16 for receiving the goods to be transported. As is common with such vehicles, the vehicle 10 includes a pneumatic braking system (not specifically illustrated) and which includes an air compressor 18 driven by the tractor engine 13. For purposes to become apparent, the trailer body 14 is designed so that it may be closed such that the space 16 is relatively air tight and sealed to the atmosphere.

The refrigerating apparatus for conditioning the enclosed space 16 is illustrated schematically in FIG. 2, and includes an evaporator 20 and fan 22 mounted 'at the front end of the trailer 14. To facilitate the proper distribution of the conditioned air within the trailer, a plurality of overhead discharge conduits 24 are operatively connected to the outlet opening of the fan 22.

The remaining components of the refrigerating apparatus are typically mounted beneath the trailer 14 in the container 26, and include a compressor 28, a condenser 30, a receiver 32, and a prime mover 34 such as a gasoline engine for driving the compressor 28 and fan 35. As is conventional with a refrigeration producer of this type, an expansion valve 36 controls the flow of refrigerant fron the receiver 32 to the direct expansion evaporator 20, wherein a change of refrigerant from the liquid phase to a gaseous phase results in a reduction of temperature.

To selectively draw a partial vacuum within the enclosed storage space 16 of the trailer, there is provided a conventional vacuum pump 40 which communicates with the space 16 via the line 42. The pump 40 is powered by the motor 34 acting through an electromagnetic clutch 44. The clutch 44 is adapted to be operatively engaged to interconnect the motor 34 and pump 40 by a manually operable electrical switch 46. For convenience, the switch 46 may be located within the tractor 12 so as to be operable by the driver during transit.

As a further aspect of the present invention, the pressurized air generated by the air compressor 18 of the braking system is employed to selectively pressurize the enclosed space 16. More particularly, the air compressor 18 is connected via the hose 50 and manually operable valve 52 to the space 16 in the manner schematically illustrated in FIG. 2. The valve 52 is normally located within the tractor 12 so that both this valve and the switch 46 may beconveniently actuated by the driver to selectively control the pressure conditions within the refrigerated space 16.

In describing the operation of the above apparatus during a typical shipment of perishable goods, it will be assumed that hot fresh produce is loaded into the trailer 14 directly from the fields where grown. in such case, the driver of the vehicle will initially close the electrical switch 46 to engage the vacuum pump 40 to create a partial vacuum within the space 16. The resulting reduction in pressure facilitates the evaporation of the surface moisture on the goods and results in their rapid cooling. Typically, thevacuum pump 40 is designed to maintain a partial vacuum of at least about one inch of water below atmospheric pressure within the space 16, and normally the pressure is maintained between about 1 to 3 inches of water below atmospheric pressure. When the desired temperature is reached, the driver opens the switch 46 as well as the valve 52 such that the pressurized air from the braking system is directed into the space 16 to increase the pressure therein. Typically, the air compressor 18 will maintain a pressure of at least about one-half pounds per square inch above atmospheric pressure within the space 15, and normally the pressure is maintained between about /2 and 4 pounds per square inch. This pressurization may be maintained for a relatively long period of time represented by a long cross-country haul to market, and serves to retard the evaporation of the natural moisture or fluid from the goods which would normally occur during this long period of time.

In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terrns are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

That which is claimed is:

1. In an automotive trucking vehicle including a tractor engine for propelling the vehicle, a trailer body defining an enclosed space for receiving the goods to be transported, and braking means for resisting movement of the vehicle and including an air compressor operatively driven by said tractor engine, the combination therewith of a refrigera-ting apparatus for conditioning said enclosed space and perishable food products or the like disposed therein, said refrigerating apparatus comprising refrigeration means for cooling the air within said enclosed space,

means for selectively drawing a partial vacuum within said enclosed space to increase the rate of evaporation of moisture from the food products disposed there-in and thereby increase the rate of cooling of such products, and

means for selectively pressurizing said enclosed space to reduce the rate of dehydration of the food products disposed therein, said pressurizing means including means operatively connecting said air compressor to said enclosed space, and valve means interposed in said connecting means for regulating the flow of compressed air from said air compressor to said enclosed space.

2. The combination as defined in claim 1 wherein said refrigeration means includes a prime mover independent from said tractor engine, and said means for selectively drawing a partial vacuum within said onclosed space includes a vacuum pump and means for selectively operatively connecting said prime mover to said vacuum pump.

3. The combination as defined in claim 1 wherein said vacuum means is adapted to draw a partial vacuum of at least about one inch of water below atmospheric pressure within said enclosed space.

4. The combination as defined in claim 8 wherein said pressurizing means is adapted to pressurize said enclosed space at least about one-half pounds per square inch above atmospheric pressure.

5. A refrigerating apparatus for conditioning an enclosed storage space and perishable food products or the like disposed therein, said refrigerating apparatus comprising:

a vapor compression cycle refrigeration producer for cooling the air within the enclosed space and including a compressor, a condenser, an evaporator, and a prime mover operatively connected to said compressor,

means for selectively pressurizing the enclosed space to reduce the rate of dehydration of the food products disposed therein,

vacuum pump means for selectively drawing a partial vacuum within the enclosed space to increase the rate of evaporation of moisture from the food products disposed therein and thereby to increase the rate of cooling of such products,

an electromagnetic clutch means for selectively operatively connecting said vacuum pump means to said prime mover, and

switch means for manually controlling engagement of said clutch means and thereby for mechanically interconnecting said vacuum pump means and said prime mover and therebydriving both said compressor and said vacuum pump means.

UNITED STATES PATENT oEETcE CERTIFICATE OF CORREQ'HQN Patent No. 3, 786, 652 Dated January 22, 1974 Inventofls) Andrew T. Bolynn It is certifiedthat error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 10, "space 15" should be space 16-- Colurnn 3, line 29, "refrigera-ting" should be -refrigerating- Column 4,11% 15, "claim 8" shol lld be claim 3-- Signed and sealed this 23rd day of April 197i (SEAL) Atte st 2 EDWARD I IDFLETCHERJRO Ca MARSHALL DANN Attesting Officer Commissioner of Patents 

1. In an automotive trucking vehicle including a tractor engine for propelling the vehicle, a trailer body defining an enclosed space for receiving the goods to be transported, and braking means for resisting movement of the vehicle and including an air compressor operatively driven by said tractor engine, the combination therewith of a refrigera-ting apparatus for conditioning said enclosed space and perishable food products or the like disposed therein, said refrigerating apparatus comprising refrigeration means for cooling the air within said enclosed space, means for selectively drawing a partial vacuum within said enclosed space to increase the rate of evaporation of moisture from the food products disposed there-in and thereby increase the rate of cooling of such products, and means for selectively pressurizing said enclosed space to reduce the rate of dehydration of the food products disposed therein, said pressurizing means including means operatively connecting said air compressor to said enclosed space, and valve means interposed in said connecting means for regulating the flow of compressed air from said air compressor to said enclosed space.
 2. The combination as defined in claim 1 wherein said refrigeration means includes a prime mover independent from said tractor engine, and said means for selectively drawing a partial vacuum within said enclosed space includes a vacuum pump and means for selectively operatively connecting said prime mover to said vacuum pump.
 3. The combination as defined in claim 1 wherein said vacuum means is adapted to draw a partial vacuum of at least about one inch of water below atmospheric pressure within said enclosed space.
 4. The combination as defined in claim 8 wherein said pressurizing means is adapted to pressurize said enclosed space at least about one-half pounds per square inch above atmospheric pressure.
 5. A refrigerating apparatus for conditioning an enclosed storage space and perishable food products or the like disposed therein, said refrigerating apparatus comprising: a vapor compression cycle refrigeration producer for cooling the air within the enclosed space and including a compressor, a condenser, an evaporator, and a prime mover operatively connected to said compressor, means for selectively pressurizing the enclosed space to reduce the rate of dehydration of the food products disposed therein, vacuum pump means for selectively drawing a partial vacuum within the enclosed space to increase the rate of evaporation of moisture from the food products disposed therein and thereby to increase the rate of cooling of such products, an electromagnetic clutch means for selectively operatively connecting said vacuum pump means to said prime mover, and switch means for manually controlling engagement of said clutch means and thereby for mechanically interconnecting said vacuum pump means and said prime mover and thereby driving both said compressor and said vacuum pump means. 